<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			/* .span2{
				color: green;
			} */
			
			/* 子代选择器 > */
			.box2>.ppp>span{
				/* color: orange; */
			}
			
			/* 后代选择器 */
			.box2 span{
				color: red;
			}
			
/* 			.box1 span{
				color: red;
			} */
			
			/* 并集选择器 都*/
			.box2 span, .box1 span{
				color: pink;
			}
			
		</style>
	</head>
	<body>
		<div class="box1">
			<span>我是box1下的span</span>
		</div>
		
		<div class="box2">
			<span>box2子级span</span>
			
			<p class="ppp">
				<span>我是box2下的span</span>
			</p>
			
			
		</div>
		
	</body>
</html>